Lightning-arrester.



w. n. GHABKY'.

LIGHTNING ABBESTEB.

(Applicgtion filed Mar. 7, 1901.)

Patented July 9, I90! (Id Model.)

NITED STATES ATENT FFICE.

LIGHTNING-ARRESTER.

SPECIFICATION formingpart Of Letters Patent NO. 677,973, dated July 9, 1901.

Application filed March 7,1901. Serial No. 50,257. (No model.) i

To all whom it may concern:

Be it known that I, WILLIAM D. GHARKY, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented new and useful'lmprovements in Lightning-Arresters, of which the following is a specification.

My invention relates todevices for protecting telephone instruments from lightning discharges coming over the line during electrical storms, such discharges being of high tension and often of sufficient volume to destroy the insulation of the magnet-windings, rendering the instruments inoperative.

The object of the invention is to produce a lightning-arrester suitable for the protection of telephone instruments, and especially adapted for those placed at individual subscribers stations. To meet the requirements of such an arrester, the construction should be simple and cheap as well as effective, and as the device must be placed in a conspicuous place upon the instrument-cabinet it is desirable that it should be of a neat and pleasing character.

In attaining my object I provide three substantially parallel metal strips of brass spanned by a carbon block, from which they are separated by a perforated sheet of mica, the carbon block being in electrical connec tion with the central metal strip. I also provide means for maintaining said carbon block and mica sheet in constant and firm contact with each other and the mica sheet with the strips, whereby circuit-conductors terminating upon the side strips are brought into close juxtaposition to but insulated from the central strip.

My invention is illustrated in the accompanying drawings, wherein the same characters of reference indicate the same parts throughout, and in which- Figure 1 is a perspective View showing my new lightning arrester mounted complete upon the backboard of a telephone instrument. Fig. 2 is a sectional side view of the same on the line as a: of Fig. 1. Fig. 3 shows the three strips forming the base of the arrester, the carbon block and its accessories having been removed. Fig. 4 is a side sectional View of one of the side strips. shows the perforated mica disk.

Fig. 5

Referring to the drawings, A is the central upper portion of the backboard of a telephone instrument, where my arrester is preferably placed. The metal strips B, G, and O, which are preferably brass punchings, are mounted parallel upon the backboard, leaving a small space between each, the lower ends of the strips 0 O being bent at right angles and thrust through holes in the backboard. The central strip is secured at its upper end to the board A by a binding-screw, the threaded shank b of which passes through the board and the strip and takes in the body of the binding-post b. A nut b is then screwed upon the bolt, adapted to secure a wire, and a lock-nut Z1 screwed'down firmly upon nut 19. The lower end of the strip B is fastened to the board by a wood-screw b and has uprising from it a screw-threaded post 0t, upon which are mounted the operative parts.

The strips 0 O are each secured to the board A by a binding-post 0, similar to the binding-post securing the upper end of strip B, and by a wood-screw 0 as shown in Fig. 4.. The outer edge of each of these strips is curved to give a circular outline, having the post Ct on the central strip as a center.

The post a carries a carbon disk M, which overlies the three metal strips, but is separated therefrom by the mica washer a having perforations a Overlying the carbon disk upon the post a is a spring-washer (1 cut in the form of a Greekcross, the arms thereof being forced into contact with said disk by the nut 01., screwed down upon the post a. The carbon disk is thus held in close proximity to but separated from all the metal strips, it being in electrical connection with the central strip B through post a and springwasher a A lock-nut a is then screwed down on the post a against nut a to prevent the latter becoming loosened or detached.

The terminals of the instrument-wiring are brought up through grooves on the back of board A and are soldered to the'tai1s'O of strips 0 and 0'. When the instrument is in place, the line-wires are secured to the binding-posts on the strips G and C, respectively, and the ground-wire to the binding-post upon strip B.

Plug-sockets 1 and 2 are. provided and suitable plugs therefor, (the latter not shown,) by

means of which either or both sides of the line may be grounded through the strip 13.

As the strips 0 0 lie in close proximity to the strip B, a heavy charge of static electricity upon the line will easily jump across the space and find a path to ground, While lighter charges will bridge the short air-gap between the strips 0 O and the carbon disk at through the perforations in the mica washer a and so to ground through strip 13.

Besides being highly efficient this arrester as a whole forms a very pleasing ornament to the telephone instrument.

Having described my invention, What I claim, and desire to secure by Letters Patent, 1s

1. In a lightning-arrester of the class described, a central metallic strip and two parallel strips in close proximity thereto lying substantially in the same plane, a metal post uprising from one end of the central strip, a carbon block carried by said post and in electrical connection therewith, and overlying portions of the three strips, and a perforated mica disk between the carbon block and the strips, substantially as described.

2 In a lightning-arrester of the class described three strips of metal lying substantially parallel to each other and in the same plane, and separated by an air-gap, a screwthreaded metal post uprising from the central strip near one end thereof, a sheet of mica having perforations carried by said post and overlying a portion of each strip, a carbon block also carried by said post and'overlying said mica sheet, a spring-washer overlying the carbon block, and a nut engaging the threads upon the post and adapted to maintain the parts in fixed relative position, substantially as described.

In testimony whereof I have affixed my signature'in presence of two witnesses.

WILLIAM D. GI'IARKY.

Vi itnessesz GRANVILLE L. Rnrrnw, PAULINE DANIEL. 

